Composting: A Science

Compost            Everybody knows that compost is beneficial to a garden, and most people use it. But a lot of people don’t really know why it’s healthy, or how it works. Compost is used to provide added nutrients to plants and vegetables; this helps them grow bigger and larger than they normally would. Compost is much more than just throwing away all of your scraps into one pile. For optimal compost, you must understand the science within the pile.

The three key ingredients to a successful compost pile are oxygen, nitrogen, and carbon. Getting the oxygen is easy; it’s as simple as turning or rotating your compost pile every so often, and keeping it moist. The tricky part is keeping a balanced ratio of carbon and nitrogen.

Compostable materials can be broken down into two categories, green and brown. The brown materials are generally full of carbon, while the green materials are full of nitrogen. The ideal ratio is about 30 parts carbon to 1 part nitrogen. This does not mean you need 30 pounds of dry leaves for every pound of banana peels. Usually using a 2:1 ratio of greens to browns will give you a 30:1 carbon/nitrogen ratio. Some examples of green materials are garden waste, soil, coffee grounds, etc. Whereas brown materials usually consist of drier things like dried leaves or nut shells.

If this ratio is unbalanced, the compost is not as effective and can even be damaging to your garden. If there is too much carbon the pile grow cold and decomposition slows down, and if the nitrogen content is too high, you will end up with high ammonia content and a stinky pile. Using compost that isn’t ready or unbalanced can cause your plants to look stunted and yellow, and will also prevent germination.

You will know when your compost is done when you can no longer recognize the materials. It should be dark brown, the same temperature as the outside air, and should have little or no smell. The texture should be crumbly and almost fluffy. Once the compost appears finished, let it sit for 2-3 weeks to ensure that it is stabilized before use.


Tips from our friends at the Urban Garden Project

Leaves are great resource for gardens! Leaves make great mulch – you can just put them on top of your soil, nice and thick and they will protect your soil and all its nutrients, over the winter months. (Mulch can also be used in the summer around growing plants to keep your weeds down and moisture in.)

If you have a yard of your own, or are working in a community garden, don’t forget to have a spot in your garden to pile the leaves and make some leaf mold. Leaf mold is essentially just well rotted leaves. It is an amazing soil conditioner, and its biggest attribute is that it holds moisture like nobodies’ business (leaf mold can hold 500% of its weight in water!). This makes it a great substitute for peat moss and an excellent addition to soil for those of us who don’t get out to water every day. It also supports important little organisms in your soil, increasing your soil health and making nutrients available to our plants, a must for any organic gardener.

How To Make Leaf Mold:

1. Collect all your leaves and put them in a big square pile (think at least 4 ft by 5 ft.)
2. If you have a lawn mower, run the leaves over with the mower to shred them, this will greatly quicken the decomposition process. If not, just pile ’em up anyway.
3. Make sure the pile is moist, you may want to cover it with a tarp to keep the moisture in if it is drying out.
4. If you want some extra work, or a faster result, give it a turn every now and then, keep an eye on the moisture etc.
5. If you want to make the pile hot you can add some fresh manure.
6. If you want to add some nitrogen to the pile add some “green” material such as grass clippings, spent hops from your local brewery or coffee grinds from the neighbourhood cafe.
Just remember to add these additional materials in layers with the leaves.

Then you just need to wait. Leaf mold can take anywhere from 6 months (with shredding, manure, moisture, turning etc.) to 2 or 3 years (just pile ’em and leave ’em method). So it’s good to do it in an unused space in your garden and make a new pile every year so you’ll have a continuous supply.

Tips from Del Seto of Side-By-Each Farm

Interested in vermicomposting? Here’s what you need to get started:

1. A home for the worms. The worm bin can either be a plastic container, or home-made from plywood, though she recommends the rubbermaid. A good size for a bin is about 50L. Aeration holes should be cut or drilled into the top of the bin and around the perimeter of the top.

2. Bedding. Newspaper strips, cardboard (clean – without inks, tape, etc.), shredded fall leaves, chopped up straw, sawdust, or peat moss (moistened) can be used.

3. And of course, the worms! (Find out about ordering worms at the end of this post.)

Your worm bin can be located in a number of places – the kitchen, garage, basement, closet. Wherever you choose, the location should be a dark, well-ventilated room, as long as the room temperature does not drop below 4 degrees Celsius.

Red wigglers will eat half their weight in food scraps every day. So for every pound of red wigglers, feed them half that weight in food waste. Feed them once or twice a week. Bury the food waste by pulling aside some of the bedding, add the waste and then cover it up. Del suggested wrapping the food scraps in newspaper, which she referred to as their “lunch”. Each time you feed your worms, choose a different location. In other words, rotate where you give them their lunch.

If you are doing it right, there should be no odor. If you are not, it is easy to fix, usually by adjusting moisture, or oxygen levels (so, by simply adding more bedding in many cases, or by taking the lid off the bin for a bit). Del sometimes puts her bin by an open window, so that her worms get plenty of air circulation. She also stores her food scraps in the refrigerator to avoid fruit flies and odor.

What to feed your worms:

-Egg shells (crushed is better), coffee grounds and unbleached filters, fruit and veggie peelings, tea bags (staples removed), breads, grains, peanut hulls. Do not put the following in your worm bin: Dairy products, fats, meats, bones, oil or oily foods (like peanut butter).

Harvest the compost from your bin every 2-3 months, when the original bedding has turned into an indistinguishable mass and the food waste has disappeared. To harvest, move the contents of the bin to one side, and add new food and new bedding on the opposite side. The worms will leave the old pile for the new one in search of food. After a few days, remove all the finished castings. A trick that Del suggested, is to put a light over the bin when you are ready to harvest your compost. The light drives the worms deeper into the pile, making it easy for you to remove the worm castings at the top of the pile. Sift out any contents that are not fully decomposed and leave them behind. You can use your worm castings (vermicompost) right away, or store it in a bag or bucket with a cover to keep moisture in.

Why go through all of the effort?

Worm castings are a nitrogen-rich natural fertilizer, which is totally organic and one of the best soil additives / plant food known to humankind. Worm compost is very concentrated, so a little goes a long way. You can add it directly to your garden, or mix some with potting soil. You can sprinkle some on top of the soil of house plants. In addition to containing unusually high populations of beneficial microorganisms crucial to healthy root systems, castings also naturally aerate the soil, retain high moisture levels, and release nutrients slowly over time. If these aren’t enough reasons, have you checked out the price of worm castings lately? You can save a tonne of money by making your own! Besides, it is a fun and rewarding experience to vermicompost at home!

Sourcing your worms:

Unfortunately we couldn’t locate a source for red wigglers in NS.

You can purchase red wigglers from Cathy’s Crawly Composters. However, please note that Cathy is unable to ship to NS until the weather warms up in the Spring.

Before you order, consider how much kitchen waste you produce and remember that for every 1/2 lb. of waste, you will need 1 lb. of worms. Try to get a group of folks together to place an order and save when buying bulk. Most start out with 1 lb. of worms. Your worms will reproduce and as your population grows, you can add more bins, or give some away as a starter to your friends. Good luck!

A great resource for learning more about vermicomposting is Worms Eat My Garbage by Mary Appelhof.

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